P0480-COOLING FAN 1 CONTROL CIRCUIT
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
With the ignition on. Battery voltage greater than 10 volts.
- Set Condition:
An open or shorted circuit is detected in the radiator fan relay control circuit for more than 2.7 seconds. One Trip Fault. Three good trips to turn off the MIL.
| Possible Causes |
| INTERNAL (A16) FUSED B+ CIRCUIT |
| INTERNAL (F1) FUSED IGNITION SWITCH OUTPUT CIRCUIT |
| (N201) COOLING FAN NO.1 RELAY CONTROL CIRCUIT OPEN |
| (N201) COOLING FAN NO.1 RELAY CONTROL CIRCUIT SHORTED TO GROUND |
| LOW SPEED RADIATOR FAN RELAY |
| PCM |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1. LOW SPEED RADIATOR FAN RELAY OPERATIONIgnition on, engine not running.
With a scan tool, actuate the Low Speed Radiator Fan Relay.
Is the Cooling Fan Relay operating?
Yes
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go To 2
2. (A16) FUSED B+ CIRCUIT
Turn the ignition off.
Remove the Low Speed Radiator Fan Relay.
Using a 12-volt test light connected to ground, probe the (A16) Fused B+ circuit.
Does the test light illuminate brightly?
Yes
- Go To 3
No
- Repair the open or short to ground in the (A16) Fused B+ circuit. Inspect the related fuse and repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3. (F1) FUSED IGNITION SWITCH OUTPUT CIRCUIT
Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (F1) Fused Ignition Switch Output circuit.
Does the test light illuminate brightly?
Yes
- Go To 4
No
- Repair the open or short to ground in the (F1) Fused Ignition Output circuit. Inspect the related fuse and repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
4. LOW SPEED RADIATOR FAN RELAY RESISTANCE
Turn the ignition off.
Measure the resistance of the Low Speed Radiator Fan Relay Coil.
Is the resistance between 60 to 80 ohms?
Yes
- Go To 5
No
- Replace the Low Speed Radiator Fan Relay.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
5. (N201) COOLING FAN NO.1 CONTROL CIRCUIT OPEN
Disconnect the C3 PCM harness connector.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis
Measure the resistance of the (N201) Cooling Fan No.1 Relay Control circuit from the Relay to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 6
No
- Repair the open in the (N201) Cooing Fan No.1 Relay Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
6. (N201) COOLING FAN NO.1 CONTROL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (N201) Cooling Fan No.1 Relay Control circuit at the Relay connection.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the (N201) Cooling Fan No.1 Relay Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go To 7
7. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Replace Powertrain Control Module per Service Information.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)